package com.zhongcw.test.java.md5;


import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Md5Util {
    public static void main(String[] args) throws NoSuchAlgorithmException {

        long startTime = System.currentTimeMillis();

        String str = "123abcABC.";
        System.out.println("before--->" + str);
        System.out.println("after---->" + Md5Util.getMd5(str));

    }

    public static String getMd5(String str) throws NoSuchAlgorithmException {

        MessageDigest messageDigest = MessageDigest.getInstance("MD5");

        byte[] bytes = str.getBytes();

        bytes = messageDigest.digest(bytes);

        StringBuffer md5str = new StringBuffer();

        // 把数组每一字节换成16进制连成md5字符串
        int digital;
        int len = bytes.length;
        for (int i = 0; i < len; i++) {
            digital = bytes[i];

            if (digital < 0) {
                digital += 256;
            }
            if (digital < 16) {
                md5str.append("0");
            }
            md5str.append(Integer.toHexString(digital));
        }
        return md5str.toString().toUpperCase();
    }

    public static String getMd51(String s) {
        char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

        try {
            byte[] btInput = s.getBytes();

            // 获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = MessageDigest.getInstance("MD5");

            // 使用指定的字节更新摘要
            mdInst.update(btInput);

            // 获得密文
            byte[] md = mdInst.digest();

            // 把密文转换成十六进制的字符串形式
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str).toUpperCase();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}
